Constipation and leakage of stool (fecal incontinence) are common bowel problems. Sometimes they are caused by malfunction of anal and rectal muscles or weakness of these muscles. Biofeedback therapy is an instrument-guided treatment program designed to improve the coordination and strength of these muscles. Incontinence training is a method of improving bowel function in patients with stool leakage. The greater the muscle contraction, the greater the activation of displayed lights on the instrument when the instrument is switched into the incontinence training mode. Similarly, for patients with constipation, the greater the muscle relaxation, the greater the activation of displayed lights on the instrument when the instrument is switched into the constipation mode.